Method of making composition tubs



March 19, 1929.

J. OLSON 1,705,780

METHOD OF MAKING COMPOSITION TUBS Filed June 5, 192

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JOHN 0L50N.

Patented Mar. 19, 1929.

UNITED STATES JOHN OLSON, E MINNEAPOLIS, MINNESOTA.

METHOD MAKING COMPOSITION TUBTS.

Application filed June 5,

This invention relates to a composition container and particularly to such a container as a small tub such as used in packing and shipping butter and similar materials. Butter ,6 tubs are now used in large numbers and these tubs are as a rule made of wood and usually of a plurality of staves held together by hoops. It isan object of this invention to provide a container such as a small tub made from a composition of materials including Wood pulp and casein in suitable proportions, said tub being formed under pressure whereby a rigid, solid and durable article is produced. It is a further object ofthe invention to provide such a container or tub of composition material including wood pulp and casein, which tub is. formed in dies under very great pressure, the resulting article then being dipped in a chemical such as formaldehyde whereby said chemical acts on the casein and produces a water proof article. It is still another object of the invention to provide a novel method of forming a container such as a tub, which consists in mixing fibrous material such as wood pulp in different proportions with casein, pressing the material in dies to form the article under great pressure whereby the casein is caused to permeate the fibrous material, which dies preferably are heated, and in dipping the article so formed in a chemical such as formaldehyde whereby the casein is chemically acted upon and rendered water proof.

It is still another object of the invention to produce a one-piece tub of a fibrous composition material including casein, which tub prefefrably is heated to render the same water roo v. p These and other 'objectsand advantages of 40 the invention will be fully set forth in the following description made in connection with the accompanying drawings, in which like reference characters refer to similar parts throughout the several views and in which Fig. 1 is a view partly in side elevation and partly in vertical section of the apparatus used in producing the article and carrying out the method; and

Fig, 2 is a horizontal section on line -22 so of Fig. 1.

In making the container or tub a fibrous material isused, and while various materials may be employed, one material which has been found to be very suitable is wood pulp. This pulp is formed by grinding up ordinary wood 1926. Serial No. 113,931.

into comparatively fine form.- This ground wood pulp is then mixed with water and with caseln in certain definite proportions. While these proportions may vary somewhat in prac I tice, it has been found that by mixing one pound of pulp with one ounce of casein and the necessary water to form a substance of semi-fluid or plastic consistency gives very good results. The casein acts as a lubricant and gives the mixture a great capacity to flow. I The material so mixed is then pressed to form between dies. While various types of apparatus might be used for this purpose, one suitable type of apparatus is that illustrated in the drawings. This apparatus comprises a frame having a supporting platform or shelf 3 on which is supported a female die 4 and a male die 5. The female die 4 is shown as having a frusto-conical recess or chamber therein ,with a central projection 4 at its bottom, thus forming an annular groove atthe outside and bottom of said chamber adapted to form a projection 6 around the bottom and exterior of the tub 6 which is shown between the .dies 4 and 5 in Fig. 1.

The die 4 has a multiplicity of small holes or passages '4" extending outwardlyg from the chamber therein which are arran ed in vertical rows, the passages in each row communicating with a groove 4 extending vertically or longitudinally at the exterior ofthe die 4. The bottom portion of the die 4 is for-med as a separate piece :4 and this piece also has a plurality of holes or passages 4 extending downwardly therethrough arranged in radial rows, the passages in each row communicating with grooves 4 extending radially at the bottom or exterior of the member 4". Member 4 is carried on a plunger 4 which extends down centrally through an opening formed in the bottom of the member 4. The member 4 normally rests in a chamber formed at'the bottom ofthe member 4. The die 4 is surrounded by a casing 7 of general cylindrical shape having spaced walls to form a chamber 7 therein and inlet and outlet steam pipes 8 and 9 respectively are shown extending through the wall of the member 7 and in the chamber 7 by means of which said member may be heated to thus heat the die 4. The casing 7 has a cylindrical chamber formed centrally thereof with a conical lower portion which receives and supports the die 4, and said chamber 7 rests upon the platform v The male (1 5 is of frusto-conical shape adapted to extend into the chamber in the die 4 and to 11: 7e its walls substantially parallel to the wal s of said chamber and spaced therefrom. The die 5 has a flange 5 extending over the top of the die 4 and said die 5 is carried on a vertically extending plunger 5".

The plunger 5 extends through a bearing 10 X formed in an arm 10 projecting from a frame 11 which preferably will form part of'the machine frame comprising a platform 3.

The top of the plunger 5 has an enlarged head 5 received in a recess inthe bottom of a vertically reciprocating member or plunger 12, said head 5 being held in said recess by a coupling collar 13 secured to the member 12 by the circumferentially spaced screws 12.

The member 12 is adapted to be reci )rocated container or tub.

by any suitable means and to app y great pressure to the plunger 5". The plunger 5" also has a keyway or spline 5 therein adapted to receive a key carried in the gear 14 which gears meshes with a gear 15 secured to a shaft 16. Gears 14 and 15 are received between the bearing 10 and an arm projecting therefrom and a lower arm 10 also forming bearings for the plunger 5 and the. shaft 16. The shaft 16 carries a pulley 17 disposed in an opening in the arm 10, which pulley is adapted to be driven by a belt 18 connected to some suitable driving means.

The casing 7 has a pipe 19 threaded into the central opening therethrough which has a projecting boss through which passes the plunger 4. A packing nut 20 is placed on this boss on the pipe 19, and pipe 19 is adapted to be connected to some suitable pump or suction means.

The plastic composition prepared as above set forth is either heated or cold placed in the die 4 when the die 5 is elevated above the die 4. The plunger 5 and the die 5 are then pressed down by means of the member 12 and the material is pressed into the shape of the tub as shown in Fig. 1. The apparatus is designed to place a pressure of from 25 to 400 tons per square foot on the material between the dies. This pressure causes the'casein to intimately and thoroughly permeate the Wood pulp with which it is mixed and the moisture or water in the material is expressed out through the small openings 4. The pipe 19 may be connected to a suction means such as a pump and suction applied to the grooves 4 and 4'. This will act to draw the moisture or water through the holes 4" so that all moisture and water is uickly drawn from the composition materia or tub. The die4 may also be heated while the material is pressed. Enough material is placed in the die so that the flange 5' can substantially engage the top of die 4 and the material will be distributed so as to form a unitary and perfect When the die 5 has been brought substantially to its lowest position,

,cient for the purpose intended.

being thus comthe die can be rotated through its plunger 5" and the gears 14 and 15 which will be driven through the pulley 17 and the belt 18. This gives a smooth and very finished surface to the inside of the tub. After this operatlon the die 5 is again raised to be well above the die 4. The member 4 is then elevated slight- 1y to move the container or tub 6 upward in the .die 4. The pressure on the material has causedthe same to be extremely solid and hard, so that the tub can now be readily lifted from .the die 4. The casein which has permeated the pulp acts as a binder, so that the resulting tub has great strength. After the tub is removed from the apparatus, the same is dipped in a suitable chemical such as formaldehyde. This chemical acts on the casein to form a waterproof substance. The treatment by this formaldehyde also results in the production of a completely sterilized container. The containers or tubs are now allowed to stand for a suitable period and are then ready for the final operations. These operations consist in placing the metal hoops about the bottom corner of the tub and in providing suitable coverings. The bottom hoop is provided to protect the bottom corner of the tub when'in use and if desired, one or more intermediate hoops may be placed about the tub, one of which preferably will have means for connection to the cover, for holding the latter in place.

From. the .-.above description it is seen that applicant has provided a simple and eflicient method of producing a composition tub and has also produced a simple one-piece composition tub. The article has been made and tested in actual use and found to, be very ellihard, strong and durable and makes an excellent container for packing and shipping butter and similar materials. The surface of the container is hard, sterile, and waterproof and does not absorb moisture, grease or odors from the material. The containers are much simpler and can be produced much more inexpensively than the wooden tubs which have heretofore been commonly used.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions. of the article and apparatus used, and in the steps and sequence of steps of the method, without departing from the scope of applicants invention, which, generally stated, consists in the method and apparatus and article disclosed and defined in the appended claims.

What is claimed is 1. The methodof making a composition container or tub which consists in mixing merely wood pulp and casein in definite proportions together with water, to make a plastic mass, then pressing said material between dies under very high pressure. whereby the casein is caused .to permeate the wood pulp The same is and a unitary rigid article is produc'ed'and proportions of one pound of pulp to one relatively moving said dies and article at high ounce of casein, with suiiicient water to make speed to finish said article. a plasticmass, then pressing said material 2. The method of making a composition between inner and outer dies under 25 tons 5 container or'tub which consists in mixing or more pressure per square foot whereby the wood pulp and casein substantially in the casein is caused to thoroughly permeate the proportions of one pound of pulp to one wood pulp, then rotating said inner die and ounce of casein, with sufficient water to make afterwards removing said tub from said dies. a plastic mass, then pressing said material 6. The method of making a composition 1 between dies under 25 tons or more pressure container or tub which consists in mixing er square foot whereby the casein is caused wood pulp and casein substantially in the proto thoroughly permeate the wood pulp and a portions of one pound of pulp to one ounce solid homogeneous and-rigidarticle is proof casein, with sufficient water to make a duced. plastic mass, then pressing said material be- 3. The method of making a composition tween heated perforated dies under from 25 container or tub which consists in mixing to 400 tons pressure per square foot to'exwood pulp and casein in definite proportions press the water therefrom, whereby the casein together with water, to make a plastic mass, is caused to thoroughly permeate the wood then pressing said material between dies unpulp, and then dipping the resulting article 20 der very high pressure whereby the casein in formaldehyde whereby said formaldehyde is caused to permeate the wood pulp and a acts on the casein to produce a waterproof unitary rigid article is produced, then dipsubstance. ping said article in formaldehyde whereby 7. The method of making a composition 05 said formaldehyde acts on the casein to procontainer or tub which consists in mixing duce a waterproof or insoluble coating on with water, wood pulp and a relatively small said article. a proportion of casein to make a plastic mass,

4. The method of making a composition then pressing said mass between perforated container or tub which consists in mixing dies under very high pressure, whereby some wood pulp and casein substantially in the of the water is expressed the casein is caused 3 proportions of one pound of pulp to one to permeatev the wood pulp and a unitary ounce of casein, with suflicient water to make rigid article is produced.

a plastic mass, then pressing said material 8. A method of making a composition tub between dies under 25 tons or more pressure which consists in mixing wood pulp, water er square foot whereby the casein is caused and a relatively small proportion of casein,

35 to thoroughly permeate the wood pulp and to make a plastic mass, pressing said means a solid and rigid article is produced, then between inner and outer dies, one of which is dipping said article in formaldehyde whereerforated, under high pressure to form said by said formaldehyde acts on the casein to 'tub, heating said dies and rotating said inso produce a waterproof coating on said article. ner die to give a smooth finish to the inner 40 5. The method of making a composition side of said article.

container or tub which consists in mixing In testimony whereof I afiix my signature. wood pulp and casein substantially in the JOHN OLSON. 

